1. Field of the Invention
The present invention relates to a technology for control display on a screen by a plurality of processing units (tasks and applications), and more particularly to an allocation of the display area.
2. Description of the Related Art
When a plurality of applications display on one screen, a window system, such as X-Window System, has been used. In these window systems, each application displays acquiring the respective window (multi-window).
Japanese Laid-Open Patent Application HEI4-274289 discloses a device which groups windows acquired by each application, and displays or does not display in group units.
Also in accordance with Japanese Patent Laid-Open No. 1-100662, when contents displayed on a plurality of windows are inter-related, these plurality of windows are simultaneously displayed so that the user can easily understand the display contents.
However, with the conventional display based on a multi-window, what application displays on what display area basically depends on the application. Therefore it is possible for an application to display a window which overlaps with the window displayed by another application. When such a problem occurs, the user must change the position of the window which is overlapped by another window in order to view the display of the window, which is troublesome.
In satellite broadcasting TV, where users need not change the positions of windows, different applications must be used to prevent the overlapping display of windows. For such devices, a conventional window system cannot be used.
In accordance with the Japanese Laid-Open Patent Application HEI4-274289, multiple windows specified by an application are grouped so as to improve the operability of each window, but the handling of overlapping of windows depends on the application. In other words, an undesired display of multi-windows is inevitable, and the above mentioned problems are not solved.
In accordance with the Japanese Laid-Open Patent Application HEI1-100662, the handling of overlapping windows also depends on the application, where an undesired display of multi-windows is still inevitable, and the above mentioned problems are not solved.